Agent: refactor such that it can be used as a base class

In the future, this will make it much easier to  refactor into a 
library.

The plan is to allow Agent to have subsystems, but only those which are 
related to managing peer-to-peer message and not application-specific 
stuff. For example, wemight have a MeshRouting subsystem that listens 
for messages and conditionally forwards them based on the content of the 
message.

src/lib/agent/Agent.mjs

@@ -3,6 +3,7 @@
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
+import { EventEmitter } from 'events';
 
 import log from '../io/NamespacedLog.mjs'; const l = log("agent");
 
@@ -12,8 +13,10 @@ import PeerServer from './PeerServer.mjs';
 import parse_peer_name from '../parse/peer_name.mjs';
 import hostuuid from '../io/hostuuid.mjs';
 
-class Agent {
+class Agent extends EventEmitter {
 	constructor(config) {
+		super();
+		
 		this.config = config;
 	}
 	
@@ -58,6 +61,8 @@ class Agent {
 		this.server.on("message-peerlist-request", this.__send_peer_list.bind(this));
 		this.server.on("message-peerlist-response", this.__handle_peer_list.bind(this));
 		
+		this.server.on("message", this.handle_message.bind(this));
+		this.server.on("destroy", this.handle_destroy.bind(this));
 		
 		///
 		// 4: Start listening
@@ -112,6 +117,44 @@ class Agent {
 		else
 			l.log(`No new peers in peerlist sent by ${peer.id_short}`);
 	}
+	
+	handle_message(peer, event_name, msg) {
+		this.emit("message", peer, event_name, msg);
+		this.emit(`message-${event_name}`, peer, msg);
+	}
+	
+	handle_destroy(peer_info) {
+		const index = this.connected_peers.indexOf(peer);
+		if(index > -1)
+			this.connected_peers.splice(index, 1);
+		
+		// Remember, this is the address:port of the connecting port, NOT the server we would connect to to re-establish a connection!
+		l.log(`Peer ${peer_info.id_short} from ${peer_info.remote.address}:${peer_info.remote.port} disconnected`);
+		this.emit("disconnect", peer_info);
+	}
+	
+	/**
+	 * Sends a message to 1 or more peers.
+	 * @param	{string|Peer|string[]|Peer[]}	peer_id		Either the peer id or the peer itself to which we should send the message. May also be an array of arbitrarily mixed items - in which case the message will be sent to all the specified peers in parallel. The order which peers are messaged is undefined.
+	 * @param	{string}		event_name	The name of the event to send.
+	 * @param	{Object}		msg			The message itself to send.
+	 * @return	{Promise}		A Promise that resolves (or potentially rejects) when the message has been sent.
+	 */
+	async send(peer_id, event_name, msg) {
+		return await this.server.send(peer_id, event_name, msg);
+	}
+	
+	/**
+	 * Sends a message in parallel to all peers to which we have an established
+	 * connection.
+	 * The order which peers are messaged is undefined.
+	 * @param	{string}		event_name	The name of the event to send.
+	 * @param	{Object}		msg			The message itself to send.
+	 * @return	{Promise}		A Promise that resolves (or potentially rejects) when the message has been sent.
+	 */
+	async broadcast(event_name, msg) {
+		return await this.server.broadcast(event_name, msg);
+	}
 }
 
 export default Agent;

src/lib/agent/PeerServer.mjs

@@ -96,8 +96,12 @@ class PeerServer extends EventEmitter {
 		if(index > -1)
 			this.connected_peers.splice(index, 1);
 		
-		l.log(`Peer ${peer.id_short} from ${peer.address}:${peer.port} disconnected`);
+		this.emit("disconnect", {
-		this.emit("disconnect", peer.remote_endpoint);
+			id: peer.id,
+			id_short: peer.id_short,
+			// Remember, this is the address:port of the connecting port, NOT the server we would connect to to re-establish a connection!
+			remote: peer.remote_endpoint
+		});
 	}
 	
 	/**